Publications by authors named "Annalakshmi O"

Precise estimation of individual radiation dose utilizing biomaterials (fingernail, bone, and tooth) is very challenging due to their complex sample processing. Despite, tooth enamel, the most mineralized tissue of tooth is used for this purpose due to its high radiation sensitivity and ability to produce radiation induced long lived CO radicals. However, human teeth are not always available, and invasive nature of sample collection adds to the complexity making dose estimation difficult.

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Surface mount electronic devices (like resistors, capacitors, and inductors) extracted from the portable electronic devices (mobile phones, USB drives, etc.) have been studied for dose reconstruction using luminescence techniques for radiological or nuclear emergencies. In this work, carbon coated ceramic resistors removed from the electronic instruments are analyzed using thermo luminescence (TL) technique for the retrospective dose reconstruction.

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Radiation has widespread applications in medicine. However, despite the benefits of medical radiation exposures, adverse long-term health effects are cause for concern. Protein and gene biomarkers are early indicators of cellular response after low-dose exposure.

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Interventional radiology-based imaging is the preferred choice for diagnosis and therapy of many complex diseases, despite possible adverse effects of the radiation exposures. We have measured induced DNA damage and changes in gene expression in relation to entrance surface dose (ESD) in peripheral blood samples of patients (n = 51) who underwent neuro-interventional radiological procedures. The ESD values, measured by thermoluminescence dosimetry, were 4.

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Recent epidemiological studies in various cohorts confirm that radiation induced cataract may occur at a threshold dose as low as 0.5 Gy. ICRP has recognised the higher radiosensitivity of eye lens and recommended to reduce annual eye lens dose limit from 150 to 20 mSv.

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Lithium tetraborate doped with manganese synthesised by solid-state sintering technique exhibits a dosimetric peak at 280°C. The high-temperature glow curve results in no fading for three months. The sensitivity of Li2B4O7:Mn is determined to be 0.

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Polycrystalline powder samples of BaSO(4) doped with Eu(2+) were prepared by solid-state reaction in different reducing atmospheres. Photoluminescence (PL), thermoluminescence (TL), TL kinetic and dosimetric studies have been carried out in this phosphor. The TL glow curve of BaSO(4):Eu(2+) showed only a single peak at 513 K unlike other phosphors and the TL intensity is about three to four times higher than that of CaSO(4):Dy, which is currently used as the radiation dosemeter for personnel monitoring in India.

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This paper describes the successful development of the co-precipitation technique for the preparation of a high-sensitive dysprosium-doped calcium sulphate (CaSO(4):Dy) thermoluminescent dosimetry (TLD) phosphor with dosimetric glow peak at approximately 230 degrees C which is a desired development in the field of radiation protection dosimetry. The main advantages of this co-precipitation technique over the conventional recrystallisation technique of phosphor preparation are: (i) preparation time is very less; (ii) quantity of sulphuric acid evaporated is insignificant; (iii) higher TL sensitivity -20% more than the present material; (iv) better glow curve structure; (v) lesser glow peak shift and better linearity to gamma and (vi) uniform crystal morphology and lower grain size-all grains are mostly cuboidal in shape, quite uniform and small (average size about 25 microm), suitable for manufacturing teflon discs in as-prepared form. Optimum values of various parameters in the method of preparation for a batch of 20 g CaSO(4):Dy phosphors to obtain maximum TL sensitivity, with favourable glow curves are studied.

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